Lesson 6 — Query Plan Awareness

Topics

• Read EXPLAIN output at a basic level
• Build intuition for query plans
• Make sound relational design tradeoffs
• Prisma
• TypeORM
• PostgreSQL schema design
• Parameterized SQL queries
• Migrations
• Connection pooling
• Pagination and relational modeling
• Refactoring an existing service to use persistent storage
• Replace the in-memory task store with PostgreSQL
• Design tables with proper keys and timestamps
• Add at least one relational feature such as labels, comments, or task history
• Write and apply migrations
• Refactor route handlers to use `pg` or `postgres.js`
• Add pagination to `GET /tasks`
• Use transactions where multi-step writes require consistency
• Verify safe query construction throughout the application
• Updated repository
• Schema and migration files
• README with local PostgreSQL setup instructions
• Sample SQL or API walkthrough
• Short note explaining relational design decisions

This lesson is finished